Integrated effect of seeding rate, herbicide dosage and application timing on durum wheat (<i>Triticum turgidum</i> l. var durum) yield, yield components and wild oat (avena fatua l.) control in south eastern Ethiopia

Abstract

Knowledge of optimal combinations of crop densities, herbicide dose and time of application could improve the effectiveness and net benefit of commonly used herbicides. A study was conducted at two locations in SARC on-station and farmer's field, South Eastern Ethiopia for two years from 2007 to 2008. The experimental design was randomized complete block (RCB) design with split-plot arrangement. Durum wheat (Triticum turgidum) seeding rates (recommended, 25% and 50% plus recommended rate) were arranged in the main plot. Four wild oat (Avena fatua) herbicide, Topik, doses (0, 25, 50 and 100 % of the recommended dose) and three timing of applications (14 DA, 32 DAE and 50 DAE) were used as sub-plot treatments. The treatments were compared to determine their effect on durum wheat yield, yield components wild oat densities and control efficacies. Durum wheat seeding rates significantly influenced grain and biomass yield, spike per unit area and kernel weight. Seeding rate of 225 kg ha-1 produced highest grain yield (3810.4 kg ha-1) while 150 kg ha-1 recorded the lowest. Mean wild oat density count before herbicide application timings varied over the two locations averaging 37 and 87 seedlings m-2. Increasing seed rate by 25 and 50% increased wild oat control efficacy by 16.9 and 21.5% respectively. Spraying the herbicide at later growth stages caused greater wild oat seedling density and reduced wheat yield at both locations. The highest efficacy (94.04%) was obtained in the second time of application (30 DAE) of 1 l lit ha-1. The highest reduction in population density was occurred in 100% herbicide rate. There was a general decline in wild oat density in the early application and as the herbicide dose increased, but the effect of seeding rate varied very slightly. In contrast to the wild oat control efficacy the highest grain yield ha-1 was obtained in the first application date (14 DAE). Durum wheat yield losses in the absence of herbicide application were increased by about 16%. Maximum yield (3870.73 kg ha-1) was obtained at 100% of the herbicide dose very closely followed by 50 and 25% of the recommended rate reducing durum wheat yield only by about 1.6 and 2% respectively. Durum wheat seeding rate, herbicide dosage and application timing had statistically no significant interaction effect.

Weeding Intensity and Plant Population Affect Yield and Yield Components of Food Barley (Hordeum Vulgare L.)

“…The present study in agreement with the ndings, Haile [73] who reported that the lowest seeding rate (100 kg ha -1 ) resulted in harvest index of 3.851 tons ha -1 , which was signi cantly lower than harvest index obtained at the other seeding rates (150 and 175 kg ha -1 ). Likely, Burgos [85] and Abiot [52] reported that harvest index increased as seeding rate was increased from 50 to 100 kg ha-1 and from 100 to 150 kg ha -1 respectively.…”

“…The result shows that there are more effective tillers (6.06) at this location. Farmers' tactics included frequent two-time weeding (2W) but a smaller number of tillers (0.42).The ndings of Durem Wheat, as reported by Haile and Girma, [73] also con rmed.…”

Management Strategies for Herbicide-Resistant Weeds by Using Different Herbicides in Sequential Application for Effective and Safe Weed Control in Wheat.

“…In contrast, the lowest straw yield/fed was obtained from Eferst at the recommended rate alone in both seasons, respectively. Similar findings were reported by Pourazar and Baghestani (2010), Zhu et al (2010) and Haile and Girma (2010) who indicated that Topik herbicide gave high grain yield with the highest stability in wheat. However, Knezevic et al (2010) indicated that application of herbicides with adjuvants caused the increase of yield in comparison with plots treated with herbicide alone.…”

Integrated weed management in wheat by using sowing time, seed rate and herbicides

“…Hence, enhanced interspecific competition in favour of wheat plants is negatively reflected in the total weight of weeds per unit area. These results are in line with the Bulut et al (2010) and Haile and Girma (2010) who suggested that crop density would be naturally less under low seeding rate, leaving many resources available for weeds and enabling them to establish quickly.…”

“…As plants compete for available resources at high plant densities, extremely low plant densities may allow weed invasion. Wheat yield loss due to weed-infested fields was reduced using higher than recommended seeding rates (Haile, Girma, 2010). High plant density due to a high seeding rate results in greater intraspecific competition for moisture, sunlight, and essential nutrients (Iqbal et al, 2020).…”